Wheels having differing designs are known in various documents, including, among others, U.S. Pat. No. 8,308,604 entitled “Omni-wheel based driving device with belt transmission mechanism;” U.S. Pat. Pub. No. 2008/0295595 entitled “Dynamically balanced in-line wheel vehicle;” U.S. Pat. No. 7,233,221 entitled “Magnetic wheel for vehicles;” U. S. Pat. Pub. No. 2012/0200380 entitled “Magnetic wheel;” and an article by Lee, Seung-heui, et. al. entitled “Recognition of Corrosion State Based on Omnidirectional Mobile Robot for Inspection of CAS for Oil Tanker Annual Conference 2008.” The specific designs and features of the wheels and vehicles described in these documents can best be appreciated by a review of their respective disclosures.